NaturalONE on Windows 2008 server many licenses and ports

Hi All

I have installed naturalONE on my windows 2008 server. I have a license for 30 users.
When the first users creates a workspace the default port is localhost:8080, the second user gets port 8081. Every user therefore also gets port 8081.

How do you ensure that each users workspace has their own port?

Thanks
Joanne